1. Field of the Invention
The invention relates to a tube conveyor, in particular a tube conveyor in which the endlessly revolving conveying means such as the belt of a conveyor is guided in the interior of rolls which are attached in a ring-like manner and whose axes extend substantially transversally to the direction of conveyance and is substantially shaped into a tube.
2. Description of the Prior Art
In order to convey material to be conveyed as is produced in mining, for example, between different locations, belt conveyors, among other things, are used in practice.
It has been noticed that conventional belt conveyors are merely suitable for transport on straight paths since curves cause a different change in the length of the two side edges of the conveyor belt which is not possible with a conventional straight belt conveyor.
This problem is solved by the use of a tube conveyor.
In this process a part of the conveyor belt is rolled together into a tube-like conveyor belt, thus firstly providing the possibility to also build curved conveyor belt pathways and secondly preventing any spilling of the material to be conveyed, which is a problem frequently encountered in practical operation where bulk materials are concerned.
U.S. Pat. No. 5,042,646 A and U.S. Pat. No. 4,526,272 A describe such tube conveyors. The partly tubular cross section of the conveying belt is achieved by arranging the same within conveying rolls which are arranged in a ring-shaped manner transversally to the direction of conveyance. The return of the empty conveying belt is performed outside of the carrying rollers arranged in a ring-shaped way.
The problematic aspect of the tube conveyors, as are described in U.S. Pat. No. 5,042,646 A and U.S. Pat. No. 4,526,272 A, is the fact however that the return of the loose side of the belt (the unloaded strand) occurs underneath the loaded strand, which means that the loose side is guided from below to the loaded strand and partly encompasses the same in a U-shaped manner.
This leads to a course of the belt which is similar to that of conventional belt conveyors. The loaded strand is situated at the top and the unloaded strand is situated below. For the purpose of supporting the unloaded strand which is supplied to the carrier rolls attached in a ring-shaped manner, additional supporting rolls are necessary outside at the lower side of the unloaded stand. Said supporting rolls considerably increase the amount of required work for the installation of such a tube conveyor. Moreover, such externally arranged additional supporting rolls contribute substantially to the production of noise in such a tube conveyor.